I've seen Jill Enfield's work frequently in magazines and books, and was thrilled when I found out she was writing her own text. I teach experimental photography at a university, so any book of this nature that comes on the market, I buy. When this came in the mail from Amazon.com (promptly, I might add) I was impressed. Watson Guptill knows how to lay out a textbook so that it appeals to the reader, and is well supported by images, not only with examples of the processes but with "how to" pictures, also. It is user friendly, especially for those who are somewhat newer to the photographic medium and experimental in nature. That said, I learned new things (e.g. the chapter on tintypes) that I will use in my experimental photography class!
These topics are included: black and white infrared, liquid emulsion, enlarging negatives for alternative processes, ink jet transfers, polaroid processes, cyanotypes, kallitypes, platinum printing, palladium printing, tintypes, hand coloring, and other stuff. It is a good combination of what are traditionally termed "alt process" (platinum, cyanotypes, etc.) and what are more experimental things to try.
For this type of book the price at Amazon.com is excellent--most books of this caliber range from [$$$].